U.S. patent number 8,622,433 [Application Number 11/579,495] was granted by the patent office on 2014-01-07 for security document.
This patent grant is currently assigned to Giesecke & Devrient GmbH. The grantee listed for this patent is Christof Baldus, Georg Depta, Walter Dorfler, Peter Franz, Karlheinz Mayer, Max Voit. Invention is credited to Christof Baldus, Georg Depta, Walter Dorfler, Peter Franz, Karlheinz Mayer, Max Voit.
United States Patent |
8,622,433 |
Depta , et al. |
January 7, 2014 |
Security document
Abstract
The invention relates to a value document, such as bank note,
passport or the like, which has a security paper and a marking
produced with the help of a laser, the security paper having at
least one partial area with a coating, and the marking extending
over the border area between coating and security paper. Further,
the invention relates to a security paper and methods for producing
an inventive value document and security paper.
Inventors: |
Depta; Georg (Rosenheim,
DE), Mayer; Karlheinz (Augsburg, DE),
Baldus; Christof (Munchen, DE), Franz; Peter
(Pienzenau/Bruck, DE), Voit; Max (Weilheim,
DE), Dorfler; Walter (Munchen, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Depta; Georg
Mayer; Karlheinz
Baldus; Christof
Franz; Peter
Voit; Max
Dorfler; Walter |
Rosenheim
Augsburg
Munchen
Pienzenau/Bruck
Weilheim
Munchen |
N/A
N/A
N/A
N/A
N/A
N/A |
DE
DE
DE
DE
DE
DE |
|
|
Assignee: |
Giesecke & Devrient GmbH
(Munich, DE)
|
Family
ID: |
34966637 |
Appl.
No.: |
11/579,495 |
Filed: |
May 2, 2005 |
PCT
Filed: |
May 02, 2005 |
PCT No.: |
PCT/EP2005/004741 |
371(c)(1),(2),(4) Date: |
November 01, 2007 |
PCT
Pub. No.: |
WO2005/108109 |
PCT
Pub. Date: |
November 17, 2005 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20080191462 A1 |
Aug 14, 2008 |
|
Foreign Application Priority Data
|
|
|
|
|
May 5, 2004 [DE] |
|
|
10 2004 022 081 |
Jun 4, 2004 [DE] |
|
|
10 2004 027 306 |
|
Current U.S.
Class: |
283/72;
283/86 |
Current CPC
Class: |
B42D
25/29 (20141001); B41M 3/14 (20130101); B42D
25/41 (20141001); D21H 21/42 (20130101); B42D
25/355 (20141001); B42D 25/373 (20141001); B41M
5/26 (20130101); B42D 25/24 (20141001); B42D
2033/10 (20130101); B42D 2033/26 (20130101); B42D
25/23 (20141001) |
Current International
Class: |
B42D
15/00 (20060101) |
Field of
Search: |
;283/72,85,86,92,94 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
28 36 529 |
|
Mar 1979 |
|
DE |
|
197 32 860 |
|
Feb 1999 |
|
DE |
|
198 22 605 |
|
Nov 1999 |
|
DE |
|
0 918 649 |
|
Jun 1999 |
|
EP |
|
1 580 553 |
|
Dec 1980 |
|
GB |
|
WO 03/023723 |
|
Mar 2003 |
|
WO |
|
WO 2004/009371 |
|
Jan 2004 |
|
WO |
|
Other References
Dictionary.com; Related Words for "inscribed". cited by examiner
.
International Search Report dated Aug. 1, 2005 in
PCT/EP2005/004741. cited by applicant.
|
Primary Examiner: Grabowski; Kyle
Attorney, Agent or Firm: Bacon & Thomas, PLLC
Claims
The invention claimed is:
1. A value document, comprising a security paper and a marking
produced at least in the security paper with the help of a laser,
wherein the security paper includes at least one partial area with
a coating, wherein the coating comprises a transparent layer being
transparent to laser radiation of a selected wavelength and an
absorbent layer being absorbent to laser radiation at the selected
wavelength and being located between the transparent layer and the
security paper, wherein the marking is made by the laser in the
coating and extends into the security paper through a border area
between the coating and security paper, and the laser influences
the coating and the security paper differently such that the
appearance of the marking changes in said border area, wherein the
marking is shown as a negative representation formed by gaps
present only within the coating and extending through the
transparent layer and the absorbent layer and is shown as a
positive representation in the form of color alterations of the
security paper outside the at least one partial area with the
coating, wherein the security paper has additives, which change or
alter color in the presence of a laser, outside the at least one
partial area with the coating to make the positive representation
of the marking.
2. The value document according to claim 1, wherein the coating
comprises at least one metal layer.
3. The value document according to claim 2, wherein the marking is
present in the area of the coating in the form of gaps in the metal
layer which run into a color change of the security paper in the
border area with the security paper.
4. The value document according to claim 1, wherein the coating
comprises at least one plastic layer and one metal layer, the
plastic layer having a diffraction structure.
5. The value document according to claim 1, wherein the coating
comprises an ink mixture having at least one mixture component
absorbent to laser radiation and one mixture component transparent
to laser radiation.
6. The value document according to claim 1, wherein the coating is
of multilayer design and at least one of the layers includes the
marking.
7. The value document according to claim 1, wherein the coating has
optically variable properties.
8. The value document according to claim 1, wherein the coating
comprises either or both liquid crystalline pigments and
interference layer pigments.
9. The value document according to claim 1, wherein the marking is
present in a form selected from the group consisting of
alphanumeric characters, bar codes, patterns, graphics and
microwriting.
10. The value document according to claim 1, wherein a plurality of
markings is present on the value document.
11. The value document according to claim 1, wherein the value
document is of multilayer configuration.
12. A security paper for value documents, comprising a substrate
forming the security paper and having a marking at least in the
substrate produced with the help of a laser, wherein the substrate
includes a coating in at least one partial area, said coating
comprising a transparent layer being transparent to laser radiation
of a selected wavelength and an absorbent layer being absorbent to
laser radiation at the selected wavelength and being located
between the transparent layer and the security paper, wherein the
marking is made by the laser in the coating and extends into the
substrate through a border area between the coating and substrate,
and the laser influences the coating and the security paper
differently such that the appearance of the marking changes in said
border area, wherein the marking is shown as a negative
representation formed by gaps present only within the coating and
extending through the transparent layer and the absorbent layer and
is shown as a positive representation in the form of color
alterations of the security paper outside the at least one partial
area having the coating, wherein the security paper has additives,
which change or alter color in the presence of a laser, outside the
at least one partial area with the coating to make the positive
representation of the marking.
13. The security paper according to claim 12, wherein the security
paper is of multilayer configuration.
14. A method for producing a marking in a value document including
a security paper provided with a coating at least in one partial
area, comprising the steps: exposing the value document to laser
radiation, wherein a laser beam is guided over a border area
between the coating and the security paper, said coating comprising
a transparent layer being transparent to laser radiation of a
selected wavelength and an absorbent layer being absorbent to laser
radiation at the selected wavelength and being located between the
transparent layer and the security paper, removing a partial area
of the absorbent layer and entraining the transparent layer by
ablation, and selecting laser parameters so as to produce a marking
which is present both in the area of the coating and in the area of
the security paper and extends over the border area, and the laser
radiation influences the coating and the security paper differently
such that the appearance of the marking changes in said border
area, wherein the marking is shown as a negative representation
formed by gaps present only within the coating and extending
through the transparent layer and the absorbent layer and is shown
as a positive representation in the form of color alterations of
the security paper outside the at least one partial area having the
coating, wherein the security paper has additives, which change or
alter color in the presence of laser radiation, outside the at
least one partial area with the coating to make the positive
representation of the marking.
15. The method according to claim 14, wherein a Nd:YAG laser is
used.
16. A method for producing a marking in a security paper for value
documents including at least one partial area having a coating,
comprising the steps: exposing the security paper to laser
radiation, wherein a laser beam is guided over a border area
between coating and security paper, said coating comprising a
transparent layer being transparent to laser radiation of a
selected wavelength and an absorbent layer being absorbent to laser
radiation at the selected wavelength and being located between the
transparent layer and the security paper, removing a partial area
of the absorbent layer and entraining the transparent layer by
ablation, and selecting laser parameters so as to produce a marking
which is present both in the area of the coating and in the area of
the security paper, and the marking also extends over the border
area, and the laser influences the coating and the security paper
differently such that the appearance of the marking changes in said
border area, wherein the marking is shown as a negative
representation formed by gaps present only within the coating and
extending through the transparent layer and the absorbent layer and
is shown as a positive representation in the form of color
alterations of the security paper outside the at least one partial
area having the coating, wherein the security paper has additives,
which change or alter color in the presence of laser radiation,
outside the at least one partial area with the coating to make the
positive representation of the marking.
17. The method according to claim 16, wherein a Nd:YAG laser is
used.
Description
This invention relates to a value document, such as bank note,
identity card, passport or the like, which has a security paper and
a marking produced with the help of a laser, the security paper
having at least one partial area with a coating. Furthermore, the
invention relates to a security paper and methods for producing an
inventive value document and security paper.
Bank notes, checks, travel tickets, admission tickets and other
value documents, in particular made of paper, are equipped for the
purposes of falsification security with security features by which
the authenticity of the value documents can be checked.
In this connection it has been proposed to apply markings to a
document by means of laser radiation to obtain an irreversible and
visually readily detectable change in the document. For example, it
is proposed in DE 28 36 529 C2 to burn the serial number out of a
printing ink layer by means of a suitably controlled laser beam. In
EP 0 918 649 B1 it is proposed to repeat the identification number
by locally reducing the document thickness by means of laser
etching at another place on the document. In both above-mentioned
cases, material is thus removed by means of laser radiation.
In contrast, other approaches provide for only blackening the
substrate material by means of laser radiation. To obtain
particularly readily legible and sharp-edged markings, it is also
known to admix absorbents and carbon forming agents, for example
microground plastics, to the paper (DE 197 32 860 A1).
DE 198 22 605 A1 takes a different path. It is proposed therein to
first treat the paper substrate surface with laser energy to change
the surface structurally, and then provide said surface with an
opaque coating, for example by printing, lacquering and/or
metallizing. Previously changing the surface leads to a
recognizable change in color density, color location, luster and/or
reflection in the subsequently applied coating, thereby creating a
visible security feature.
The problem of the present invention is to propose a value document
and a security paper with an improved visual security feature which
has high falsification security, as well as a method for producing
such a security feature.
An inventive value document, such as a bank note, a passport or the
like, has a security paper and a marking produced with the help of
a laser, the security paper being provided with a coating at least
in one partial area, and the marking extending over the border area
between coating and security paper. Since the laser is guided over
the value document continuously in the form of the marking, and the
laser radiation influences the coating and the paper substrate
differently, the marking shows a different appearance in the
various areas, these different appearances running directly into
each other. The marking thus appears with perfect registration at
the transition in the border area between coating and security
paper, causing the falsification security against reproduction
obtained with said marking to be very high.
According to a preferred embodiment, the coating has at least one
metal layer, such as aluminum, gold, silver, etc. The action of the
laser radiation removes the metal layer, so that the part of the
marking located within the metal layer is present in the form of
gaps in the metal layer. Since the laser beam is guided
continuously over the border area between coating and security
paper, the negative representation of the marking runs seamlessly
into a positive representation in the area of the security
paper.
This is because the laser action leads to a color change or color
alteration of the security paper in the marked area. The type and
shade of the color alteration depends on the composition of the
security paper used. Said color change or color alteration can be
increased by suitable additives which can be contained within the
volume of the security paper, the sizing or a subsequent priming.
The type of additives used is dependent on the type of laser used
or the laser wavelength used. Additives absorbing laser radiation
can be used, such as carbon black, thermochromic substances or
titanium dioxide.
The part of the inventive marking located within the security paper
can also be of tactilely perceptible design, as described in WO
204/009371.
The inventive metal layer can be a printed layer containing metal
pigments or metallic effect pigments or a vapor-deposited or
sputtered layer.
In the latter case the metal layer is preferably prepared on a
separate carrier and applied to the security paper or value
document in the form of a label or transfer element. Such labels or
transfer elements can also have any further layers, such as a
lacquer layer in which diffraction structures are embossed in the
form of a relief. The metal layer normally serves as a reflecting
layer for the diffraction structures.
According to a further embodiment, the coating can be formed as a
laser-sensitive recording layer, whereby it has at least one
component absorbent to laser radiation of a selected wavelength. A
suitable laser-sensitive recording layer is for example an ink
mixture having one mixture component absorbent to laser radiation
and one mixture component transparent to laser radiation. The
marking is visually recognizable here due to an irreversible change
in the optical properties of the ink mixture caused by the action
of the laser radiation. The absorbent mixture component can be for
example bleached, vaporized, changed in its reflection properties
or converted by a chemical reaction into a material with different
optical properties under the action of the laser radiation.
Preferably, the ink mixture contains optically variable coloring
pigments, whereby in particular optically variable liquid crystal
pigments can be used for the mixture component transparent to laser
radiation, and for example optically variable interference layer
pigments for the absorbent mixture component.
Such a coating shows an interplay of colors upon a change of
viewing angle, whereby the perceptible color effect is a
superposition of the color effects of the various optically
variable coloring pigments. The laser action causes the color
effect of the interference layer pigments to disappear or change,
so that the lasered areas contrast in color with the surroundings.
However, the lasered areas still show an optically variable effect.
If the lasered marking extends over the border area between coating
and security paper, the optically variable portion of the marking
is carried over into a non-optically variable portion which arises
from lasering of the paper substrate. This creates the impression
that the marking was produced by different methods in exact
register.
A very similar appearance of the marking can be produced if the
laser radiation transparent and absorbent portions of the mixture
are disposed one above the other in separate layers.
For producing the marking it is preferable to use Nd:YAG lasers
with a wavelength of 1064 nm. Depending on the type of marking to
be produced, the laser can be used in continuous-wave mode or in
pulsed mode. For example, in pulsed mode it is possible to produce
a visible variation in the degree of blackening over the course of
the marking in the security paper.
The laser marking can be used to represent alphanumeric characters,
for example serial numbers of the value documents or any codes,
such as one-dimensional or two-dimensional bar codes or blind
codes, any symbols, graphics, patterns, pictures or microwriting.
Any desired alphanumeric characters, such as date, time, batch
number, or letterings are also possible. Every inventive marking
extends beyond the border of the coating into the security paper,
causing the appearance of the marking to change with perfect
registration at the transition.
The inventive value document can have further security features,
such as a security thread, an optically variable security element,
a security print, such as an intaglio print, or machine readable
security features, such as luminescent or magnetic substances. If
the value document has a security thread, the inventive laser
marking can also be provided in the area of the security thread.
The inventive value documents can also be used for protecting
products of any type.
The inventive value document is any document whose essential
component is a security paper, such as a bank note, check, visa,
label, passport page or another document to be protected made of
security paper.
The step of laser inscription is done in any stage of production of
the value document. It can thus be expedient to already provide a
corresponding marking on the security paper after production in
roll form. This is in particular the case when the security paper
is provided in endless form with a foil coating, such as a
diffractively effective, for example stripe-shaped security
element, and said security element is to be provided with an
inventive marking, as described above.
However, the step of laser marking is preferably done as one of the
last working steps in the production of the value document. If the
value documents are printed for example in the form of
multiple-copy sheets, laser marking can be done on the sheet or
already on the cut, finished value document. The latter is
expedient in particular when the laser marking is to produce
individual information, such as a serial number.
A special security-related advantage of the present invention is to
be seen in that the described effect cannot be imitated by simple
means. The use of lasers requires high investments and profound
technical know-how far exceeding the state of knowledge required
for using customary printing machines or digital printing
devices.
A further advantage of the invention is that the laser marking can
be carried out contactlessly at a speed typical of printing plants.
In particular, each document can be marked individually by for
example integrating the serial number or another individualizing
feature into the value document as a security feature.
The advantages of the invention will be explained with reference to
the following examples and supplementary figures. The described
individual features and embodiments described hereinafter are
inventive taken per se, but also in combination. The examples
constitute preferred embodiments, but the invention is in no way
limited thereto. The proportions shown in the figures do not
correspond to the relations existing in reality and serve mainly to
improve clearness.
FIG. 1 shows an inventive value document,
FIG. 2 shows a detail enlargement of the area A,
FIG. 3 shows a section through the inventive value document along
the line B-B,
FIG. 4 shows a section through the inventive value document along
the line C-C,
FIG. 5 shows a section through the inventive value document along
the line D-D,
FIG. 6 shows an alternative structure of the coating,
FIG. 7 shows another exemplary coating.
FIG. 1 shows an inventive value document 1 in the form of a bank
note. The value document 1 has according to the invention a marking
2 in the form of a numeric string which was produced by the action
of a laser beam and extends into the edge area of the bank note
1.
FIG. 2 shows a detail enlargement of the area A of FIG. 1. This
enlargement clearly indicates the inventively essential transition
of the marking 2 over the border area between coating 3 and
security paper 4 within the shown "4". At the border of the two
areas (3, 4) the marking 2 runs on seamlessly and without offset.
Due to the darker gray level of the marking in the area of the
security paper 4, the transition is clearly visible and appears
with perfect registration, which would not be attainable as such
for a printed marking.
FIG. 3 shows a section through the value document 1 along the line
B-B. In this case a coating 3 in the form of a security element is
disposed in the area of the marking 2, the security element
consisting of a transfer element. The transfer element is fastened
to the value document 1 by means of an adhesive layer 5. A metal
layer 6 is located between the adhesive layer 5 and a plastic layer
7, in particular lacquer layer 7.
FIG. 4 shows a section through the value document 1 along the line
C-C. It can be seen here that said metal layer 6 is lacking in the
area of the marking 2. During the inscription or marking process
with the laser the metal layer 6 is changed such that it is no
longer visible. The reference number 8 designates the area exposed
to laser radiation.
FIG. 5 shows a section through the value document 1 along the line
D-D. A color alteration 9 caused by the laser inscription can be
seen in the security paper (substrate) 4, which is part of the "8"
belonging to the marking and recognizable in a top view. In this
example an "8" is shown with a degree of blackening corresponding
to a dark gray level. The laser power must be adjusted to the
desired degree of blackening.
In the border area A the appearance or the representation mode of
the marking 2 therefore changes. In the area of the coating 3 the
marking 2 is shown in the form of gaps 8 in the metal layer 6, i.e.
as a negative representation, while the marking 2 is present
outside the coating 3 in the form of color alterations, i.e. as a
positive representation.
FIG. 6 shows a security paper (substrate) 20, for example a bank
note or another value document, having applied thereto a coating 22
comprising an ink mixture of two mixture components 24 and 26. One
of the mixture components 24 is transparent to the radiation of the
infrared laser subsequently used for marking, the other mixture
component 26 absorbs the laser radiation. In the area 28 the
marking layer 22 was irradiated with the marking laser with
suitably selected laser parameters in order to remove, change or
deactivate the absorbent mixture component 26 by the action of the
laser radiation.
Depending on the material used, the absorbent mixture component 26
can be for example bleached, vaporized, changed in its reflection
properties or converted by a chemical reaction into a material with
different optical properties. Altogether, the irradiation
irreversibly changes the optical properties of the ink mixture in
the area 28. Possible effects include color alteration, production
of a color change, brightening of a color, changing of the tilt
color of a special-effect ink mixture or local changing of the
polarization properties or the luminescence properties of the
coating 22.
The laser-induced change in the optical properties of the ink
mixture causes visually recognizable markings in the value
document. These can be constituted by the form of the irradiated
and modified areas 28 of the marking layer itself, or result only
in interaction with further printed layers structured for example
to contain information.
For example, an information-carrying printed layer can be provided
between the substrate 20 and the coating 22, and the change in
optical properties of the coating 22 consist in the production of
transparent partial areas 28 in an otherwise opaque layer, so that
the information of the printed layer is visible in said partial
areas after laser irradiation.
Another exemplary coating is shown in FIG. 7. A substrate 30 has
applied thereto a coating 32 which has a first layer 34 transparent
to laser radiation of the selected wavelength, an absorbent layer
36, and a second layer 38 transparent to laser radiation. At least
one of the absorbent or transparent layers contains optically
variable coloring pigments. For example, the transparent layer 34
can contain liquid crystal pigments showing a reflectance color
varying with viewing angle.
Laser irradiation has caused the absorbent layer 36 to be removed
in a partial area 40, whereby the transparent layer 38 overlying
the absorbent layer 36 was entrained therewith by the ablation. If
for example an infrared laser, such as a Nd:YAG laser with
.lamda.=1.064 .mu.m, is used for ablation, the layers 34, 38
transparent to laser radiation can be opaque and colored in the
visible spectral range. The form and shape of the removed area 40
permit the coating 32 to be provided with diverse markings, in
which for example an optically variable color effect of a liquid
crystal layer 34 stands out in contrast with a monochrome
surrounding area of a second transparent printed layer 38.
In all these examples the part of the marking produced in the
various coatings continues in the surrounding substrate material in
the form of a change in color and/or contrast.
* * * * *